Method



July 3, 1923.. AGLOU v E. L. FULLER METHOD OF MAKING INNER TUBES Filed Aug. 16. 1920 Patented July 3, 19g3. y

UNITE EN. l

ERNEST L. FULLER, OF AKRON, 01H10, tbl? :.lEGrlifOlEt TU Til-EEE G-UDYLEAR illltlll de RUBBER Application filed hngust'le, 192i). Serial lilo. 403,685.

Be it known that l, Ennns'r L. ilumina, a citizen of the United States, residing Akron, in the county of Summit and State of Uhio, have invented nen7 and useful lm- `provements in the Method oi Making lnner Tubes, of which the following is a specilication.

My invention relates to a method ot torming inner .tubes for pneumatic tires, and is particularly concerned with the formation of the valve-receiving opening in the inner tube.

l-leretoliore di'fiiculty has been experienced in the manufacture ot inner tubes in 'rorminp; the valve-receiving openings in the inner tubes, Which have been punched by a suitable mechanical device, but the openings are :frequently not provided With straight Walls, which, of course, makes it dillicult to obtain an air tight joint with the valve stem.

The principal object of my invention is to provide inner tubes with openings which shalljbe uniformly straight Walled and con sequently insure a suitable union with the valve stems.

@ther and ancillary objects will be appar ent from the following detailed. description oi my invention in conjunction with the companying' drawings.

In the drawings, Fig. l is a plan view ot a sheet oit rubber and a mandrel employed in a preliminary step oli forming an inner tube thereon.

Fig'. 2 is a sectional vien of a tubular member which is utilized in forming an inner tube in accordance with my invention Fig. 3 is a sectional view taken substan tially along' the line 3 3 ot Fig. l.

In practicing` my invention an inner tube is formed by the usual method ot Winding a sheet ot rubber upon a straight mandrel, Which is then removed trom the straight mandrel, disposed upon a curved mandrel and subjected to a vulcanizinp; heat. Before the sheet of rubber is rolled upon the first mandrel a valve patch is placed in a suitable position upon the rubber and a tubular member is disposed in the openiinii provided in the 4valve patch. The valve patch and the tubular member carried thereby are, ot course, interposed between the convolutions of rubber When it is rolled upon the mandrel.

`When the tor-med tube is subjected to heat in a vuleanizingg,I oven the rubber becomes sott and permits the tubular member to cut an opening; therein, which action is supplemented by a slight tension which is created 'when the rubber is vulcanized.

.its shown in Fig'. l, a sheet et rubber l, of suitable dimensions, has a valve patch 2 formed of iabric, or other suitable material., disposed in a proper position upon the sheet l. rlhe ,patch is, oi course, provided with a central opening 3 into which a tubular member d is placed. The tubular member d may be a 'lerrule formed of any suitable metal, the iluction ot which is to provide a valvereceivingl opening in the tor-med tube.

.er mandrel 5 is placed adjacent one edge ot the rubber sheet l. an d the sheetrolled thereon, which ol course disposes the patch Q between the ccnvolutions oiti rubber. rlhe rolled tube ot rubber is then removed from the mandrel and disposed upon a circular mandrel, not shown, and Wrapped by Winding; a strip ot' untreated librous material about the tube. rlhe structure thus termed is disposed in a suitable heating` chamber and heat `applied to cure the rubber sheet l. lWhen the heat is applied, the rubber is solitened and the l'errule Ll cuts through the rubber, due to its softened condition, and to a tension that is created in the rubber by the vulcanization, which is also supplemented by the confining action of the Wrapping ot [ibrous material.

litter the tube has been thoroughly cured it is removed :trom the oven. rlhe fibrous Wrapping is removed and the tube stripped vlroni the mandrel, the ierrule l being taken out et the opening which it has made in the tube.

llt Will be appreciated that by this method the valve-receiving opening provided in the tube is straight Walled and, therefore, insures a good union with the valve stem.

rlFhe above described method contains the operations that are generally followed in the manufacture ot inner tubes and it is not unduly complicated by the additional step oi disposing the metal tube in a valve patch to provide the valvc-receiving` opening in the tube.

Although l have illustrated and specilically described a method ot forming inner tubes in accordance with my invention, it is obvious that minor changes may be made in the sequence of operations and in the' selection of materials, Without departing from the spirit and scope of my invention, and I desire, therefore, that no limitations shall be imposed except such as are indi catedin the appended claims.

What lI claim is:

1. The method of making inner tubes that comprises disposing a ierrule upon a sheet of uncured rubber, forming a tube oft' the rubber, subjecting it to heat andpressure. and removing the ferrule therefrom,

2; The-methodof making inner tubes that comprises disposing a valve patch upon a sheet of uncured rubber, disposing` a metallic tubein the opening of the valve patch, rolling the sheet to form a tube,

fwrapping the tube With a fibrous strip to compact'it and effect a piercing` thereotl by the metallic tube, subjecting the tube to heat to` vulcanize the rubber, removing the metallic tube from the cured rubber.

3. The method of makinginner tubes that comprises, disposing a valve patch upon a sheet of uneured rubber, placing a metallic tube partially Within the opening of the valve patch, forming an inner tube oit the sheet of rubber, and removing the metal tube therefrom.

4. A; method of making inner tubes tor pneumatic tires which consists in forming a tube from vulcanizable rubber composition, making a reinforcing valve-base with a central opening, assembling the valve-base and tube, settinga hole-molding-element in the opening in the reinforcing valve-base andcuring -the tube.

5. A method of making inner tubes for pneumatic tires which consists in forming a tube Jfrom vulcanizable rubber composition, making a reinforcing valve-base of strain resisting threads and with a central opening, incorporating the valve-base in the tube and introducing a hole-moldingelement in the opening therein, curing the tube to shape, and linally removing the hole-molding-element.

6. The method otniaking inner tubes that comprises disposing a valve patch upon a sheet of uncured rubber, disposing a metallic-cutting-element in an opening ol" the valve patch, rolling the sheet to form a tube, Wrapping the tube with ay ibrous strip to compact it and eii'ect a cutting thereof by the metallic-cutting-element. subjecting the tube to heat to vulcanize the rubber, and removing the metallicecutting-element from the cured rubber.

7. A method of making inner tubes for pneumatic tires which consists in forming a tube from vulcanizable rubber composii tion, making a reinforcing valve-base with a central opening, assembling the valvebase and tube, setting a hole-cuttilig-e10nlent in the opening in the reinforcing valve-base and curing the tube.

ln witness whereof, I have hereunto signed my name in the presence of two subscribing Witnesses.

ERNEST L, FULLER. Vitnesses JOHN E. KEATING, L. M. HARTMAN. 

